Numbers appearing in parentheses at the end of a sentence refer to specific references cited at the conclusion of this specification immediately before the claims.
Formulations containing phosphatidylcholine and bile salts (phosphatidylcholine bile salt formulations, PBF) are increasingly being utilized to treat localized fat accumulation (1-8). Several open label clinical studies have reported promising results using injections of PBFs for the treatment of localized fat accumulation, including lower eyelid fat herniation and “buffalo hump” lipodystrophy (1-3).
Phosphatidylcholine is a natural phospholipid that is an essential component of cell membranes and is important for normal cellular membrane composition and repair. Phosphatidylcholine is also the major delivery form of the essential nutrient choline. Choline itself is a precursor in the synthesis of the neurotransmitter acetylcholine, the methyl donor betaine and phospholipids, including phosphatidylcholine and sphingomyelin among others. Phosphatidylcholine is also involved in the hepatic export of very-low-density lipoproteins.
Bile salts have been used to improve the aqueous solubility of phosphatidylcholine and more recently, medications like amphotericin B, Taxol®, and diazepam (9-14). Highly purified phosphatidylcholine can be combined with the secondary bile salt sodium deoxycholate, an anti-microbial, benzyl alcohol, and water to form a stable, mixed micelle preparation that can be rapidly sterilized and used for intravenous administration (12). Pharmaceutical preparations of this mixture, known as Essentiale® and Lipostabil®, are marketed in other countries for treatment of liver disease and hyperlipidemia, respectively (12, 15).
Rittes first reported that injections of a PBF into subcutaneous fat reduced infraorbital fat herniation (1). Since then, physicians have been using the pharmaceutical preparations or similar, compounded PBFs, to treat lower eyelid fat herniation, as well as fat deposits on the thighs, abdomen, upper back, chin, and arms (2, 3, 5). These PBFs often lack the dl-alpha-tocopherol (vitamin E), B-vitamins, and adenosine monophosphate variably found in Essentiale® and Lipostabil® (2, 16).
Phosphatidylcholine formulations are associated with localized burning sensations, erythema, transient urticaria and variable degrees of pruritus all of which usually resolve within a few days. More serious sequelae of ulceration and pain have also been seen. An infectious granulomatous reaction has been reported in the thigh of a patient at the site of multiple phosphatidylcholine injections (7). Increased dosages of injected phosphatidylcholine have paralleled side effects seen with large doses of oral and intravenous formulations of Lipostabil® and include nausea, diarrhea, abdominal pain and syncope.
The mechanism whereby phosphatidylcholine-containing formulation cause reduction of subcutaneous fat deposits is unknown but several mechanisms have been proposed (4). The first is that phosphatidylcholine could reduce the size of lipocytes by stimulating lipase activity. Alternatively, the PBFs have been postulated to function as a detergent that emulsifies lipocyte cell membranes. Detergents have been used in medicine for decades, specifically, as sclerosing agents commonly used in sclerotherapy (American College of Phlebology, 2003). Detergents possess unique polar and non-polar chemical properties which facilitates emulsification of insoluble substances by reducing surface tension at their interface (17). In fact, laboratory detergents like Triton® X-100 and Empigen® BB are commonly used to disrupt the lipid bilayer of cell membranes (10, 18-21). Two major components of the PBFs, phosphatidylcholine and sodium deoxycholate, have these unique chemical properties and therefore have been used independently as detergents or emulsifying agents (9, 18, 20-25).
Surgical and non-surgical procedures for improving appearance have increased in prevalence as populations age and gain weight. Liposuction is one of the most popular cosmetic surgery procedures and involves the surgical removal of fat deposits using suction and optionally assisted by solutions to assist in fat removal. Liposuction, also known as lipoplasty or suction lipectomy, is a surgical procedure that removes fat through an incision in the skin through which a cannula is inserted. The cannula is connected to a suction source and the unwanted fat is aspirated through the cannula and discarded. Liposuction is performed under general or local anesthesia, depending on the amount and location of the fat to be removed.
The most commonly used forms of liposuction additionally use fluid injection methodologies wherein a medicated solution containing a mixture of salts, an anesthetic and a vasoconstrictor, is infused into the treatment site prior to aspiration of the fat tissue. The medicated solution helps the fat be removed more easily, reduces blood loss and provides anesthesia both during and after surgery.
In an example of adjuvant solutions for liposuction, a United States patent filed on Apr. 22, 1997 and issued as U.S. Pat. No. 5,891,083 on Apr. 6, 1999 by Capella and Capella teaches liposuction and a carrier solution containing a compound for an improved surgical procedure for removing subcutaneous fat. In one embodiment the Capella patent discloses the compound is an enzyme, particularly lipase or colipase. The enzyme is added to a carrier such as saline solution to provide a lipolysis solution. In another embodiment of the invention, Capella teaches emulsifying agents such as bile salts may also be beneficial in combination or as the primary active compound added to the solution. In every embodiment of the Capella invention, the lipolysis solution is administered for a period of time before liposuction to allow for the solution to infiltrate the fat tissue. Nowhere in Capella is the use of a lipolysis solution alone disclosed as a non-surgical means for removing fat from the body. In all examples and specific embodiments disclosed in Capella, liposuction is used as a surgical procedure for fat removal and lipase and bile salts are provided as an adjuvant to liposuction.
However, liposuction and other surgical methods of fat removal are associated with significant adverse events including temporary bruising, swelling, numbness, soreness and burning sensation, risk of infection, pigmentation changes; the formation of fat clots or blood clots which can migrate to the lungs and cause death, excessive fluid loss, which can lead to shock or fluid accumulation that must be drained, friction burns or other damage to the skin or nerves or perforation injury to the vital organs. Additionally, liposuction requires a recovery time of one to two weeks wherein the patient cannot work or perform certain daily activities. Moreover, because surgical procedures such as liposuction require local and occasionally general anesthesia, significant anesthesia-related risks are associated with surgical fat removal.
Therefore it would be desirable to have a method of removing localized fat accumulations that does not require surgery or prolonged recovery time and has fewer adverse side effects than currently available methods.